Method for producing and balancing a brake drum

Abstract

An improved method for producing a brake drum which balances a brake drum defining an inner surface and an axis. Balancing specifications are determined which correct an imbalance of the brake drum about the axis. Material is removed from the inner surface, which forms a cylindrical surface preferably defining a braking surface of the brake drum, to balance the brake drum according to the balancing specifications. It is a further feature of the invention to remove material surrounding a pilot hole initially formed in the brake drum, wherein the removal of the material also correlates to the balancing specifications.

What is claimed is:  
     
       1. A method for producing a brake drum comprising the steps of: 
       (a) providing a brake drum defining an inner surface and an axis;  
       (b) determining balancing specifications necessary to correct an imbalance of the brake drum about the axis; and  
       (c) removing material from the inner surface of the brake drum to balance the brake drum according to the balancing specifications.  
     
     
       2. The method of  claim 1 , wherein step (b) further includes determining the location and amount of the imbalance relative to a predetermined fixed reference point on the brake drum. 
     
     
       3. The method of  claim 2 , wherein step (b) further includes providing a reference mark on the brake drum at the predetermined fixed reference point on the brake drum. 
     
     
       4. The method of  claim 1 , wherein step (b) further includes determining the center of mass of the brake drum with a static balancer. 
     
     
       5. The method of  claim 1 , wherein step (c) includes forming an inner groove in the inner surface of the brake drum. 
     
     
       6. The method of  claim 5 , wherein the inner groove is a cylindrical surface formed about the second axis which is offset from the axis defined by the broke drum. 
     
     
       7. The method of  claim 6 , wherein the second axis is parallel to the axis defined by the brake drum. 
     
     
       8. The method of  claim 6 , wherein the inner cylindrical surface is formed by mounting the brake drum on a cutting machine for rotation about the second axis and operating the cutting machine to machine the inner cylindrical surface in the inner surface of the brake drum. 
     
     
       9. The method of  claim 1 , wherein step (c), material is removed from the inner surface of a liner attached to a tubular shell of the brake drum. 
     
     
       10. A method for producing a brake drum comprising the steps of: 
       (a) providing a brake drum defining an inner surface, the brake drum including a radially extending flange having a pilot hole formed therethrough, the pilot hole having a first diameter and defining an axis of the brake drum;  
       (b) determining balancing specifications necessary to correct an imbalance of the brake drum about the axis; and  
       (c) Forming an inner groove in the inner surface of the brake drum about a second axis, and machining material adjacent the pilot hole about the second axis to expand the diameter of the pilot hole, wherein the formation of the inner groove and expanding the diameter of the pilot hole balances the brake drum according to the balancing specifications.  
     
     
       11. The method of  claim 1 , wherein said step (c) includes removing material from a hole formed in a radially extending flange relative to the second axis to balance the brake drum according to the balancing specifications. 
     
     
       12. The method of  claim 10 , wherein said step (c) includes expanding the diameter of the hole formed in the radially extending flange relative to the second axis to a second diameter greater than the first diameter to balance the brake drum according to the balancing specifications. 
     
     
       13. The method of  claim 1 , wherein said step (c) includes maintaining a generally cylindrical inner braking surface. 
     
     
       14. The method of  claim 1 , wherein said step (c) includes removing material from a pilot hole formed in a radially extending mounting flange relative to a second axis. 
     
     
       15. The method of  claim 1 , wherein said step (c) includes expanding a first diameter of a pilot hole formed in a radially extending mounting flange relative to a second axis to a second diameter greater than the first diameter to balance the brake drum according to the balancing specifications. 
     
     
       16. The method of  claim 1 , wherein the brake drum defines a concentric inner surface. 
     
     
       17. The method of  claim 10 , wherein the brake drum defines a concentric inner surface. 
     
     
       18. The method of  claim 1 , wherein the brake drum defines a uninterrupted inner surface. 
     
     
       19. The method of  claim 10 , wherein the brake drum defines an uninterrupted inner surface. 
     
     
       20. A method for producing a brake drum comprising the steps of: 
       (a) providing a brake drum defining an uninterrupted concentric inner surface the brake drum including a radially extending flange having a pilot hole formed therethrough, the pilot hole having a first diameter and defining an axis of the brake drum;  
       (b) determining balancing specifications necessary to correct an imbalance of the brake drum about the axis; and  
       (c) forming an inner groove in the inner surface of the brake drum about a second axis, and machining material adjacent the pilot hole about the second axis to expand the diameter of the pilot hole, wherein the formation of the inner groove and expanding the diameter of the pilot hole balances the brake drum according to the balancing specifications while maintaining the uninterrupted concentric inner surface.